Important points
- Telescopes collect light that was emitted in the distant past and is only now reaching us here on Earth. This means that the telescope sees the universe as it once was.
- The further the telescope can see, the further back in time it can see, and the more effective it becomes as a time machine.
- Some of the world’s best telescopes use CSIRO’s cutting-edge technology to peer further into the past and answer fundamental questions about the universe.
We’ve all heard about fictional time machines, but the idea isn’t as far-fetched as you might think. When telescopes around the world observe the sky, they are effectively traveling back in time.
Telescopes are built to collect light at all wavelengths, from the visible spectrum to X-rays and radio waves.
Even light, the fastest object in the world, takes time to travel anywhere. This delay is what makes telescopes the closest thing to a time machine.
How can a telescope look back in time?
Because the universe is so vast, astronomers measure distances in units much larger than kilometers. One unit is one light year, or the distance that light can travel in one year, or about 9.5 trillion kilometers.
our sun Its distance from Earth is just over 8 light minutes. This means that the sunlight we see takes about 8 minutes to reach us.
Our closest star system, Alpha Centauri (visible with the pointer to the Southern Cross), is just over 4 light-years away. The light that reaches us today from those stars began its journey more than four years ago.
Therefore, when you look into the night sky, you don’t need a telescope and can directly see the past.
Dr. Keith Bannister As a chief engineer, he is well versed in time travel. CSIRO’s Australian Telescope National Facility (ATNF). He said the world’s best telescopes are so sensitive that they can collect light that has traveled through space for billions of years.
“They can go back billions of years into the past, to the beginning of the universe. If you want to go that far back, you need the best possible time machine: a radio telescope.”
Why radio telescopes can see farther
There’s one reason radio telescope The reason you can see farther than an optical telescope is because the radio waves emitted from distant objects are brighter.
“It’s very easy to see galaxies 10 billion light-years away with radio telescopes, but it’s very difficult with optical telescopes,” Keith says.
“Supermassive black holes at the centers of galaxies are a nuisance. They leave extremely bright signals in radio waves that can travel farther through space than visible light from surrounding galaxies.”
He also said that all of the oldest light in the universe is in radio wavelengths.
“After the Big Bang, the universe was too hot and dense for light to travel. As it expanded and cooled, light was finally able to travel freely. That early light was essentially red, but the expansion of the universe stretched it to radio wavelengths. Therefore, the earliest light in the universe must be detected by radio telescopes.”
The secret to seeing the distant universe
The more sensitive a telescope is, the deeper into the universe it can see. Sensitivity can be increased in two main ways. That is, to collect more light or to reduce “noise”.
To collect more light, you need a larger area to collect the light. Optical telescopes require larger mirrors, radio telescopes require larger dishes, or more antennas connected in an array.
Another approach is to reduce the “noise” so that telescopes only capture signals from space. As CSIRO’s ATNF chief engineer, Mark Bowen develops technology that allows telescopes to collect more of the light that astronomers rely on.
“The challenge is making sure the telescope is collecting only light from space and not from terrestrial sources, which would be classified as noise,” Mark said.
He said this could be accomplished by moving equipment into space or by designing more sophisticated equipment for use on the ground.
“Advances in semiconductors, cryogenic cooling, and amplifiers have improved radio telescope receivers, allowing them to observe weaker signals,” Mark explained.
“Advances in digital signal processing, hardware, and software allow us to collect and process more data faster and with fewer errors. All of this combines to ultimately create telescopes that can see much farther.”
A broader perspective reveals deeper clues
Sensitivity means more than just looking as far as possible.
“It’s fine to go far back in time, but if your telescope can only see one point in space, you won’t be able to build up a complete picture of what’s going on and you won’t be able to realize the full potential of time travel,” Mark said.
Traditional radio telescope receivers only see a small point in the sky called a beam.
“With the advent of highly sensitive multibeam receivers, telescopes can now simultaneously capture much larger areas of the sky while delving deeper into the universe’s past.”
CSIRO is building a cutting-edge multibeam receiver Since the 1990s, radio telescopes around the world have Mulyan, CSIRO’s Parkes Radio Telescope.
“The latest receiver in the series developed by CSIRO has arrived.” China’s FAST radio telescopethe largest single-plate telescope on Earth. ”
But the receiver is only one part of the system, and the telescope’s data processing “brain” is just as important for seeing far away.
Dr. Keith Bannister is in charge of: CracoOne of the brains processing data from the 36 antennas of CSIRO’s ASKAP radio telescope.
“There are two approaches to processing ASKAP data: Just add everything together, which is easier but less sensitive and limits the range that the telescope can see,” Keith says.
“The other method is much more sensitive and can combine the signals from all the antennas, effectively creating one giant telescope.”
But with ASKAP, Keith has taken his experience a step further across CSIRO.
“The brain behind ASKAP, CRACO, uses specialized hardware and software to simultaneously survey thousands of regions of the sky at a thousand different distances.”
“CRACO checks ASKAP data. something that explodes1000 times per second. It requires a much larger computer to operate, but it also ensures that the telescope doesn’t miss anything. ”
Assembly Required: Watch the Universe Build Itself
Professor Catherine Trott, CSIRO’s ATNF lead scientist, is an expert in looking back. She focuses on finding the most distant signals and exploring the early universe.
“By looking further afield than we’ve ever done before, we hope to detect signals at the dawn of the universe,” Kathryn said.
“We will be able to see the birth of the first stars that ever existed. We will be able to observe their birth by going far out into the universe and back to the infant universe. Before galaxies formed, the universe looked very different.”
©Scao
But what does this mean for us here on Earth?
“The early universe was filled only with hydrogen and helium gases and small amounts of lithium. Through generations of stars forming and dying, we saw other elements on the periodic table emerge,” Kathryn says.
“This helps explain the current universe and the elements found on Earth.”
From the Outback to the Otherworld: Australian Technology Deeper into Space
CSIRO has been developing radio astronomy techniques for over 80 years.building world-leading experiences across analog and digital systems, timing and signal distribution, software and data processing.
“We are in a unique position to combine all this experience into one telescope and ensure that astronomers get as much information as possible from radio telescopes of light captured from space,” Kathryn said.
Currently, the following global projects are: International SKA Observatory Telescope I have benefited from that experience. CSIRO is Help build hardware and software This will allow these two radio telescopes to see farther into the universe than ever before, helping to create the world’s best time machine.